Static eliminator in printing



Patented Aug. 24, 1943 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to a static discharge device for use indischarging the static developed on paper when passing through aprinting press.

It is old in the art to provide a high tension current which charges anumber of discharge points that are preferably placed on an insulatingbar that extends transversely across the paper as it runs through thepress. These bars are made in a number of ways, but usually consist of aseries of insulators mounted in a tube, each insulator supporting ashort wire which extends toward the paper and acts as a discharge point.In order to energize the discharge points, a high tension element isintroduced through the bar in such a manner that the electrons emittedfrom the element energize the discharge points, which constantly act toneutralize or discharge the static from the paper. When printing thinsheets or webs of paper, the static formed on the paper through themovement of one sheet over the other, is sufficient to causeconsiderable disruption of the sheets in the way they fall in the racksprovided on the press; this interferes with the mechanical handling inconnection with the printing.

A considerable amount of difficulty has been experienced in the type ofhigh tension electrode which is used in the static eliminating bar, inthat the electrode breaks down within a short time of use. Theseelectrodes have here-to-fore been made from a conducting wire set withina rubber tube which acts as an insulating covering. The rubberdeteriorates in a short time, and the high tension current begins toleak through, requiring an entire replacement of the rubber coveredterminal.

I have found that a glass terminal, charged with the mercury vapor, orequivalent material, provides the same effect in the production of therequired electrons, but does not deteriorate after long use.

In order that my invention may be more fully understood, reference ismade to the accompanying drawing, in which:

Figure l is a diagrammatic elevation, showing the discharge bar with thedischarge points projecting therefrom, and the electric transformerconnections to energize the device.

Figure 2 is a partial sectional elevation showing the insulators cutaway to expose the discharge points and the electrode for energizing thedischarge bar.

Figure 3 is a section taken on the line 3-3 in Figure 1.

Figure 4 is a perspective view of the spacing block which separates theinsulators.

Similar reference numerals refer to similar parts throughout thedrawing.

In the drawing, l is a tube, preferably of metal. 2 is a support bracketattached to the ends of the tube, and adapted to be fitted to the frameof a printing press at such a position as to be under or over the sheetor web of paper as it passes through the press. 3 is a slot milledthroughout the length of the tube, thereby forming two supporting edges3A. 4 is an insulator, preferably porcelain, which is notched on each ofits edges to conform to and engage the supporting edges 3A of the tubeI, and in such a manner that the insulators will slide in the slot 3.The insulator 4 has a hole 5, adapted to receive a short piece of metaltubing 6, and from which projects substantially at ri ht angles a metaldischarge wire I which extends through the insulator through a hole 8.In order to separate each of the insulators 4 with their dischargepoints 1 from the next insulator, a Wooden block spacer 9 is alternatelyinserted between the insulators. The spacer 9 is of sufiicient width toseparate the tube 6, mounted in the insulator 4, from the succeedingtube 6. When the insulators, carrying their discharge points 1, and thespacers 9 are mounted in the slot 3 in the tube I, a high tensionelement If] is inserted through the bore of the tube 8. This hightension element is a glass tube in which there is sealed a conductinggas, such as mercury vapor. The high tension element It) is connected tothe secondary H of a high tension transformer l2, which also has aprimary l3 connected to an alternating current supply. The other end ofthe high tension secondary H is grounded preferably to the frame of theprinting press.

In operation, the current is turned on the primary of the transformer,which induces a high tension current in the secondary coil II, whichfeeds to the high tension terminal which is preferably a mercury vaportube It). This current induces a charge in the tube 6 mounted in theinsulators 4, which is in turn carried to the discharge points 1. Asheet or web of paper [4, in passing through the press, has picked up astatic charge from friction or by induction from other sheets or webs ofpaper, and moves over or under the discharge points I, whereupon thestatic charge on the paper is neutralized or discharged.

Having described my invention, what I claim as new and desire to secureby Letters Patent, is:

1. A static eliminator for printing operations,

consisting of a gas filled high tension tube, 'a plurality of conductingbands positioned around the said high tension tube and in capacityrelation thereto, a conducting discharge point adjacent each of the saidbands and. adapted to be placed in close proximity to a sheet or web ofpaper to be printed: I

2. A static eliminator for printing operations,

consisting of a source of high tension current, a gas filled tensiontube, a plurality of conducting bands positioned around the said hightension tube and in capacity relation thereto, a conducting dischargepoint adjacent each of the said bands and adapted to be placed in closeproximity to a sheet or web of paper to be printed.

THEODORE JOHN BEREGH.

